The present invention relates to a drill for drilling crossties, particularly adapted for use in the railroad sector.
It is known that rolling stock runs on two steel rails which are kept, by various means, at a constant distance known as gauge. The rails can be supported by crossties, longitudinal ties, isolated supports and special systems, but the commonest support system is based on crossties.
Crossties are generally made of wood, since they are capable of giving the track the necessary elasticity, which is a requirement whose importance increases with the speed of the service to be performed.
The rails are usually connected to the crossties indirectly, by first connecting, with anchoring screws, the rail to a plate and then connecting, by means of spikes, the plate to the corresponding crosstie.
In order to form the holes for the passage of the fixing spikes in the ties, it is necessary to use special drilling machines which are preset for this specific function, working along the tracks of a railroad line.
These machines generally have a considerable weight and size and therefore often entail difficulties in use.
In particular, machines are commonly known which, owing to their size, have a truck of their own for traveling on the rails; machines are also known which require suitable supports to be started and/or placed in depot.
It is therefore evident that these drilling machines cannot be easily moved by a user, let alone be carried by hand.
These conventional drilling machines commonly use helical bits which have a front self-tapping element, through which the bit is forced to penetrate the material (wood) quickly but usually in a scarcely controllable manner.
A possible consequence of this is the drawback of jamming the helical bit during an intermediate step of drilling.
Moreover, since drilling operations can occur on active sections, i.e., sections affected by railroad traffic, if the bit jams in the crosstie during an intermediate step of drilling with conventional drilling machines, it would not be possible to quickly evacuate the work area should a train be about to transit.
This is due to the fact that the operation for extracting the bit from the hole formed in the crosstie is troublesome and not straightforward.
Moreover, also extracting the bit from the chuck of the drill entails difficulties and this entails a risk for the user who wishes to evacuate the work area as quickly as possible: the difficulty in extracting the drill bit in case of emergency (sudden arrival of a train) might entail the need to abandon the drill, with the risk of destroying it and of possibly damaging the train.
Another drawback of conventional drilling machines is the fact that the helical bit, driven by a specifically provided chuck, can accidentally make contact with a part of the body of the operator, with consequent danger of work accidents.